Cirrus SR22 N818GM accident near Addison, Texas

Probable cause

Maintenance personnel’s improper installation of the muffler attachment hardware, which resulted in the muffler separating in flight, thermal damage that interrupted the magnetos’ function, and the subsequent total loss of engine power.

NTSB analysis

The private pilot and flight instructor were conducting a cross-country instructional flight. During departure and while climbing through 2,800 ft mean sea level, the pilot and instructor noticed multiple avionics malfunctions and initiated a turn back toward the airport. While the airplane was turning, the engine lost all power, and the pilots noted indications of a fire. Because they were unable to find a suitable area for a forced landing, the pilot activated the airplane's parachute system. The airplane descended under the parachute into a parking lot, and the main wing spar sustained substantial damage.

Examination of the engine revealed that the engine exhaust muffler attachment hardware was not secured correctly, which allowed the exhaust collector to freely rotate. A hole near the lower right engine cowling was consistent with escaping hot exhaust gas. Several components in the right forward side of the firewall were thermally damaged, and both magneto p-leads were shorted against the engine's metal mount frame. The thermal damage interrupted both magnetos' function, which resulted in the loss of engine power.

During a pre-buy inspection of the airplane, the No. 1 cylinder base O-ring was replaced. The work order, dated 3 days before the accident, required removal of the muffler. During the muffler reinstallation, maintenance personnel likely did not correctly install the attachment hardware, which resulted in the muffler separating in flight, thermal damage that interrupted the magnetos' function, and the subsequent loss of engine power.

Text from the NTSB. Open the NTSB docket for CEN18LA392 for the full record.